It is possible in this scenario to increase the quantity received as follows:
Ribbon style menu:
From the menu select, Purchasing, Orders
Enter criteria to narrow down your search for orders using the Purchase Order Batch Selection window
Click the Display button on the Purchase Order Batch Selection window
Locate and highlight the order you wish to update in the Process Batch window
Click the Detail button
Click on a line of the order that you wish to increase the quantity received
Enter the additional quantity to receive in the Qty Received field
You will then get a message saying Do you want to receive more than the quantity outstanding?
Click Yes
Click the OK button (green tick) to save the changes
On the next screen, ensure the Update Delivery option is ticked
Click OK
The O/S Rec (outstanding to receive) column will then show a negative figure to indicate that more has been received than was originally ordered.
Classic/Module Menus style menu:
Select Purchase Orders, Transactions, Process Batch, Orders from the navigation menu
Follow from step 2 above.